1. Field of the Invention
This invention relates to an apparatus and method for sensing the profile and position of a well component, such as a tool joint or casing hanger in the well or riser bore. This information is invaluable in aiding an operator to determine if a well component is in the correct position, i.e., has the casing hanger properly landed in the wellhead housing or is it sitting high in the well bore. Similarly, the current invention can aid an operator in knowing if a tool joint or the straight outside diameter of the drill pipe is in the bore of a blowout preventer when it is time to close the rams of the blowout preventer.
The operation and placement of well components in a well bore, riser bore or blowout preventer stack is critical in oil and gas drilling operations. This is particularly true in the offshore environment where nonproductive time is very expensive. Typical operations where the present invention is applicable include the landing of a casing hanger on the subsea wellhead seat, the proper positioning and setting of the annular seal between the subsea wellhead and casing hanger or the positioning of a well component such as a test plug or tool joint at a particular level or orientation in a wellhead or blowout preventer stack.
Until recently, such operations depended on such indications as a running tally of the length of the running string or drill pipe used to lower well components into the well bore. These pipe tallies were notoriously inaccurate and as drilling requirements with regard to positioning of well components has grown more exacting, such methods of locating well components are unacceptable. Furthermore, as offshore drilling operations has moved into deeper waters, e. g., greater that 4,000 feet, more accurate methods of determining well component placement and their profiles have been needed.
Some prior advancements in drilling technology had allowed somewhat more accurate determination of well component positioning. These methods included requiring running wires from the area of the well bore to be surveyed to the water surface. This method is difficult to use in practice because of the greater water depths involved and the long lengths of wire required.
2. Description of Related Art
U.S. Pat. No. 4,314,365 to C. W. Petersen et al. shows a system for transmitting and detecting acoustic signals along a drill pipe string.
An improved method and apparatus for operating equipment in a subsea environment is disclosed in U.S. Pat. No. 4,862,426 to T. G. Cassity et al. This apparatus uses acoustic or ferrous metal detectors to determine if certain operations such as landing a casing hanger are completed.
German Utility Model Application No. 200 08 413.5 to K. Biester et al. shows a system for detecting tool joints using magnetic detection units in a planar arrangement.
The apparatus and method for sensing the profile and position of a well component in a well bore of the present invention is designed for use in a standard ram-type blowout preventer stack used in oil and gas drilling operations. The typical blowout preventer stack includes a pair of double ram preventers positioned together with an annular or xe2x80x9cbagxe2x80x9d type blowout preventer positioned above the double ram preventers. The apparatus of the present invention includes an instrumented flange with appropriate end connections to allow connecting the flange between the annular preventer and the drilling riser.
The instrumented flange is sufficiently long to allow a first plurality of sensor units to be arranged circumferentially around the axial bore of the flange in a single plane and a second plurality of sensor units to be arranged in a helical pattern along the axis of the flange. The sensor units are positioned in radially disposed pockets in the bore of the instrumented flange, but do not protrude into the bore. The pockets in which the sensor units are positioned are sealed to maintain the pressure integrity of the instrumented flange and the well bore.
Wires exit the rear of the sensor units and terminate at a signal processing unit where the output signals of the sensor units are processed. This processed information is then transmitted to a display unit at the surface whereby an operator can determine the profile and position of a well component as it passes through the instrumented flange. The present invention envisions the sensor units could be acoustic transducers, ultrasonic transducers or optical transducers or a combination thereof.
An alternative embodiment is also shown with either acoustic or ultrasonic transducers positioned on the exterior of the instrumented flange.
A principal object of the present invention is to provide a method and apparatus for sensing the profile and position of a well component in a well bore and transmitting this information to a surface mounted display unit to aid an operator in performing subsea well operations.
Another object of the present invention is to provide a method and apparatus for sensing the profile and position of a well component in a well bore utilizing acoustic, ultrasonic or optical sensors and thereby be able to sense both non-magnetic and magnetic well components.
A final object of the present invention is to provide a method and apparatus for sensing the profile and position of a well component in a well bore without requiring specialized configuration blowout preventers.
These with other objects and advantages of the present invention are pointed out with specificness in the claims annexed hereto and form a part of this disclosure. A full and complete understanding of the invention may be had by reference to the accompanying drawings and description of the preferred embodiments.